Ceramic raw material and method of making same



Patented Sept. 28, 1937 r V CERAMIC RAW MATERIAL AND METHOD OF MAKING SAME Joseph H. Weis, West Paris, Maine, assignor to Feldspathic Research Corporation, New York, N. Y., a corporation of Delaware,

'No Drawing. Application May 22,1936,

Serial No. 81,189

3 Claims. (01. 106-10) This invention'relates to the art of ceramics Table 2;Englz'sh china-clays and has for its principal object the provision of r a ceramic raw material for ceramic ware,- which Dry Total Fired I Ab o is made from domestic kaohns and has the propg g shrinkshn ksharllelk- ,lg ry in od. f f f r: 5' erties of English china clays. oggfi 1% its p er #s/sqPiri. gif

A further object is, to provide adomestic prodcent cent cent uct which can be used as a substitute for English china clays Without substantial changes in, the M n v 33.7 2.7 12. 2 8.1 41 9.6, process of utilization Max 43.3 6. 4 16.7 1.0.3 207 14.8 10 A still further object is to increase the useful- 10 ness of certain domestic kaolins. From the foregoin data, it is apparent that China clays or kaoIins a necessary i e the essential differences between domestic and t n wh W dy tu s- The E s English china clays are the higher strength in the Clays Which e used in t Country for this pllrdry state, the higher absorptions, and the higher p r commonly known a china clays, While dr ing shrinkage of domestic clays. These clays the White l ys in th Country are generally also have less average total and firing shrinkage ferred to as kaolins. The English clays are precompared t t English t 1 ferred by most potters because they produce ware These diflerences are al Shown in Tables, 4:

W a high fi Strength, and the Ware, furtherand 5 where domestic and English china clays more, is more vitrified and haslower. porosity s were incorporated in a body of the following 20 compared to ware made with domestic kaolins. composition; The use of English china clays by American Table 3 potters has been practiced since the start of the Per Cent 1 pottery Industry in this country, although lar North Carolina f ldspar 15 25 amounts of domestic kaolins were available to Flint them. However, because of the poor results 010- Kentugky ban clay 5 tained in white ware body mixtures with domestic y being studied 35 I kaolin, manufacturers of vitrified ware especially have turned to the use of the imported T containing-domesticClays 9O clays, and as a result the domestic producers have 1 U 5 lost large potential markets'for their materials. Dry Total Fired Ab The present'invention makes possible the utilifi Shrink- Shrinkshrink- Fired Q Mfg? zation of those large deposits of domestic kaolins iz g5? 23%? 353% p a Y which heretofore were considered unsuitable and cent cent cent cent 3' undesirable for use in vitrified ceramic ware, such p v as dinner ware and sanitary Ware. Min 23.2 3.3 9.5 5 s 5015 5. This ceramic raw material can be substituted Max 7 2 6806 directly for English china clays without making any ad ust t in t batch, and the resulting Table 5.B0dies containing En lish clays, 40 40 product has all of the desirable properties which I were formerly obtained by the imported clays.

In order to better understand this invention, 31 reference is made to Table 1 and. Table 2, showing tests made on five typical English china clays and nine domestic china clays of the type heretofore known, the data representing extremes. In these and subsequent tests, unless otherwise indicated, the data was obtained on ware fired to cone l1. 8 7. 3 6278 1. 51 13.7 as 7200 r 4.05

From these tests it is obvious that ware con- 45 taining English clays. have less absorption and are stronger than the similar bodies containingdomestic clays.

According to my invention, I haveso changed 10 plus r the characteristics of the domestic clays as to- TableL-Dormestic china clays make them suitable for direct replacement'of the Englishclays. I have discovered that when a Dry Total Fired feldspathic flux is added to domestic kaolins and 7 Percent en r- Sh nneshrireik- D y rmtid. fi thoroughly mixed w these kaolins in proper 55 of plasa ag per proportions, the resultant product canbe used. inv 55 -b n t 55R c n t cent place of the English clays. Iniotherwords, my. modified American kaolins can be used to replace Min 36.3 4. 6 15 10. 3 the imported English china clays without any im- Max 50.8 V 13.2 430 25.6 pairment in the quality of the finished ware, and

without the need for the user to make any changes moo in his manufacturing processes to adopt the American material.

In order to carry out this invention, I have added a feldspathic flux to one or more domestic kaolins. thoroughly blunged, the feldspathic flux is added to the blunged material and this flux is thoroughly mixed in the blunger with the clay to insure a homogeneous mass. This mixture is passed through a filter press and the excess Water removed. For continuous operation, a vacuum filter is preferred for this purpose. Further drying can be carried out on the mixture if the consumer demands a drier product. This product is now in a form where it is a direct substitute for the imported china clays, and can be used in a white wares batch to produce vitrified or semivitrified ware without any change in the method of manufacturing employed by the user.

White ware badies in general can be represented by the mix shown in Table 3. In my prepared domestfc clay, I have used, in place of the 35% English china clay which is indicated in the mix, from 3.5% to 10.5% feldspathic fluxes and from 24.5% to 31.5% of kaolin. The resulting composition is as follows:

Table 6 Per cent North Carolina. feldspar 15 Flint 35 Kentucky ball clay 15 Feldspathic fluxes 3.5 to 10.5

Kaolin 24.5 to 31.5

It will be noted that the amount of feldspathic fluxes is about 10% to 30% of the amount of kaolin. The proportion of feldspathic fluxes and kaolin are selected to produce a mixture of about the following composition:

Per cent Silica 47-57 Alumina -1 27- 37 Potash 0.2-4.0 Soda 0.2-3.0 F8203, CaO, MgO, etc. less than 3 This mixture is used as a substitute for English china clay. V

The similarity of my new ceramic raw material to the imported English china clays, is shown by Tables 7 and 8 which show the minimum and maximum test data obtained with my new raw material as compared to the same type of test 7 data on bodies containing English clays.

Table 7.Properties of bodies containing new Water is added to the clays which are Table 9 Water Dry Fired Ab- Body of plasmod. of ggi mod.of serpticity rupt. rupt. tron English 24. 3 435 12% 7% 8800 0. 2 Domestic 23. 7 430 5% 12% 7% 9000 0. 2

From the above, it is very apparent that my new ceramic raw material is the equivalent in every way to the imported English china clay, and all of the desirable properties imparted to the ware by the use of the imported material is also obtained by the use of my new ceramic raw material.

These tests and data also indicate that the utilization of domestic kaolin as a substitute and replacement for the imported English products have opened up new and larger markets for domestic kaolins which heretofore were not used for such purposes. The use of these domestic kaolins by manufacturers of ceramic ware results in lower costs by eliminating the need of importing high cost materials. The user is also assured of consistent and easily obtained supplies of do- 2. A ceramic raw material for use as a substitute for English china clay in the manufacture of white wares, consisting of a mixture of domestic kaolin and feldspathic flux, said mixture having about the following composition: silica 47-57%, alumina 27 -37%, potash 0.2-4.0%, soda 0.2-3.0%, F6203, CaO and MgO less than 3%.

3. The method of making a ceramic raw material for use as a substitute f or;English china clay in the manufacture of white wares which consists of mixing domestic kaolin with feldspathic flux in such proportions as to produce a silica content of 47-57%, an alumina content of 27-37%, a potash content of 02-40% and a soda content of 02-30%, blunging the mixture and filtering to remove excess water.

JOSEPH H. WEIS. 

